The present invention relates generally to devices for feeding a traveling strand of yarn or the like to a textile or like machine and more particularly relates to such devices of the type including a rotatable storage spool or drum arrangement adapted to receive several strand windings circumferentially thereabout for transient storage and delivery of a traveling strand by winding and unwinding thereof onto and off the spool or drum.
As used herein, the term "strand" is intended to generically define and indicate a continuous length material such as yarn, thread, filament, wire, rope, cable, tape or the like.
A relatively wide variety of spool or drum devices of the abovedescribed type are well known in the textile industry and are commonly referred to as "storage feeding devices." Representative examples of such storage feeding devices are disclosed in U.S. Pat. Nos. 3,606,975; 3,642,219; 3,648,939; 3,747,864; 3,796,384; 3,827,645; 3,928,987; 3,952,554; 4,106,713; and 4,138,866.
In basic construction, conventional storage feeding devices of the type of the above-listed patents essentially include a storage spool or drum for winding thereabout and unwinding therefrom the traveling strand to be stored and fed, a pulley or similar driving member fixedly interconnected coaxially with the spool or drum for integral driven rotation by the associated textile or like machine or by other means associated with the strand feeding arrangement therefor for effecting the on and off-winding of the strand, and a separate arrangement driven by the spool or drum for engaging the strand windings thereon to progressively displace them axially of the drum to the off-winding location. The storage spool or drum is usually constructed of axial rods or pins in a circumferentially spaced arrangement. The strand displacement arrangement may be of differing forms. In one general type of storage feeding device, the displacing arrangement includes a disc, ring, spoke-wheel or similar arrangement mounted on, extending through or otherwise associated with the rods or pins of the spool or drum at an inclination to its axis, the first nine above-listed patents exemplifying storage feeding devices of this type. One alternative form of strand displacing arrangement is illustrated in the last above-listed patent and includes a rotatable pin wheel arranged with its axis angularly oriented to the axis of the spool or drum and meshingly interdigitated therewith to be driven thereby.
Conventional storage feeding devices of the above-described type as illustrated in the listed patents are believed to be generally operable acceptably to perform their intended function. However, these devices are generally considered in the trade to be relatively expensive, due at least in part to precise parts manufacturing requirements and necessary assembly labor resulting from the engineering design of the operative association of the spool or drum and the strand displacing arrangement.
These storage feeding devices have found their widest application in controlling the feeding of yarn to textile circular knitting machines. Virtually without exception, these storage feeding devices are driven by a moving endless belt trained about the device's pulley member. In early storage feeding devices, the drive belting used was merely ordinary flatsided belting trained in frictional driving engagement with a compatible smooth circumferential belt engaging surface on the pulley member. However, as these storage feeding devices have been refined and improved to operate at the higher rotational speeds required to be compatible with conventional high speed circular knitting machines, problems have been encountered in that the required speed of movement of the drive belt often overcomes the frictional contact between the belt and the pulley resulting in unacceptable slippage therebetween which may cause yarn tension variations and even yarn breakage in some instances. To alleviate this problem, the pulley members and belting used with many present day storage feeding devices are constructed with appropriate mating surface configurations for positive timed engagement. For instance, the pulley members of many such storage feeding devices are provided with axially extending peripheral grooves to mesh with conventional timing belts of the type one side of which is formed with widthwise cogs. Other storage feeding devices employ pulley members having a peripheral circle of pins for meshing with timing belts which are of the basic flat belt type having holes centrally formed along the length of the belting to receive the pulley pins.
Some operational problems have been experienced with grooved-type timing belt and pulley arrangements in that fibrous lint and debris tend to collect in the belt and pulley grooves and to become progressively compacted therein over time by the meshing engagement between these components. Such accumulations may ultimately build to the point of preventing the desired meshing engagement between the belt and pulley. Therefore, periodic cleaning of the grooves of such belts and pulleys is required, which may be rather time consuming if a significant degree of accumulation has occurred and has become compacted.
Periodically, all such belts, both of the ordinary flat friction drive type and of the timing belt type, deteriorate and break requiring repair or replacement thereof. Most of each type of such belts typically are formed of a fabric-backed rubber material which is not inexpensive and, therefore, it is highly desirable to repair rather than to discard and replace broken belts. In uses of flat-type friction and timing belts, broken belts of these types are not ordinarily discarded but instead are conventionally repaired by splicing thereof through a process of grinding or shaving the belt ends, applying glue thereto, and joining the belt ends while applying heat thereto to bond the belt ends together. However, as will be understood, grooved type timing belts are not easily susceptible of spliced repair in this or any similar manner and, therefore, must be discarded when broken and replaced with a new belt. In addition to the apparent disadvantage of increased belt costs that result from this necessity of replacing such grooved timing belts, the replacement procedure requires a significant amount of labor and knitting machine down time in that, since yarn is fed to the machines from overhead, all yarn ends leading into the machine from overhead must be taken down to permit the endless replacement belt to be installed on the machine and then the yarn ends must be replaced in feeding position.
Moreover, the above-described conventional repair procedure for splicing flat belts has several operational and cost disadvantages. First, a relatively significant initial and ongoing investment of capital is required to be properly equipped to perform the splicing repair procedure in that special grinding and heating machines are required to perform the respective steps of shaving or grinding preparation of the belt ends and heating of the joined belt ends, both of which machines represent a relatively significant initial capital investment and further require periodic maintenance and repair in themselves, and a sufficient supply of appropriate glue is also required, which has a relatively limited shelf life. Additionally, as mentioned above, since yarn is fed to conventional circular knitting machines from overhead so that it is not possible to install a spliced belt on the machine without taking down all yarn ends being fed, it is characteristically necessary that at least the steps of gluing and bonding of the belt ends be carried out at the knitting machine with the belt in place in its operating position. As a result, replacement flat belts ordinarily are not prepared and inventoried in advance but are only prepared when needed and at the particular location required. As will be understood, the down time of machines experienced due to broken belts is at least the amount of time required to perform the splicing procedure and can be substantially greater if the belts of more than one machine break at the same time since it is normally not economically justifiable for most textile knitting mills to maintain more than one head bonding machine. Furthermore, because the conventional splicing procedure is relatively time-consuming and troublesome, it is often typical for mills to discard otherwise usable lengths of broken flat belts and to replace them with a new flat belt which requires only one splicing operation rather than splicing several shorter belt lengths.
As a result of these disadvantages some knitting mills have in recent times begun splicing broken flat friction belts by an old and well-known system of mechanical interconnection wherein a central opening is cut in one belt end with a longitudinal slit extending therefrom and notches are cut in opposite side edges of another belt end whereby the notched belt end may be inserted through the slit and central opening of the first belt end and the portion of the notched belt end between the notches positioned in the central opening to mechanically interconnect the two belt ends. As will be understood, this mechanical splicing procedure is entirely unsuitable for splicing either flat or grooved-type timing belts in that the spliced belt area would be reduced entirely incapable of the necessary ability for meshing engagement with the associated pulleys. However, as used with flat friction-type belting, this mechanical splicing procedure eliminates substantially all of the above-discussed disadvantages of the conventional glue and heat bonding procedure in that no costly special machinery or supplies are necessary and the preparation of the belt ends maybe performed both quickly and in advance whereby several small belt lengths may be inventoried for quick spliced interconnection at a machine immediately when needed to substantially reduce machine downtime to a minimum. However, certain disadvantages also exist presently with this mechanical splicing procedure in that, to date, this procedure has always been performed by hand in a relatively inexact but otherwise effectively operable manner. This latter problem has been substantially alleviated however by the invention disclosed in the aforementioned co-pending U.S. patent application Ser. No. 441,116, which provides a simple and inexpensive apparatus and method for preparing belt ends in a precise and exact manner for mechanical spliced interconnection of the above-described type.
It is also known to employ storage feeding devices in either a "positive" feeding mode wherein the strand is tangentially wound onto and off the spool or drum so that the rates of strand on and off winding are equivalent, or in a "demand" feeding mode wherein the strand is unwound from the spool or drum in a direction generally axially thereof so that such strand off-winding may occur at a rate independently of the rate of strand on-winding. Typically, conventional storage feeding devices are constructed to be operable in one or the other mode, examples of positive-type storage feeding devices being disclosed in the above-listed U.S. Pat. Nos. 3,827,645 and 4,106,713 and examples of demand-type storage feeding devices being disclosed in the above-listed U.S. Pat. Nos. 3,606,975; 3,642,219; 3,648,939; and 3,928,987. As will be appreciated, the limitation of such storage feeding devices to operation in only one mode significantly limits the flexibility of their use. Accordingly, storage feeding devices having adjustable strandoff winding guide arrangements have been proposed for facilitating selective alternative use of the devices in either a positive or a demand feeding mode, examples of such devices being disclosed in the above-listed U.S. Pat. Nos. 3,796,384 and 4,138,866.